Improvement in casing-spears



V. 'GRETTEIL Casin-g Spears.

Patented September 23,1873.

No. 143,141.v

lkw/@7720.21 @w "UNITED STATES PA'ralv'r OFFICE.

VICTOR GRETTER, OF RICHLAND TOWNSHIP, CLARION COUNTY, PA.

{MPRovEMENT IN cAslNG-SPEARS.

Specification forming part of Letters Patent No. 143,141, datedSeptember 23, 1873; application led May 14, 1873. Y

To all whomt may concern:

Be it known that I, VICTOR GRETTER, of Richland township, Clarioncounty, Pennsyl- Vania, (St. Petersburg P. 0.,) have invented certainImprovements in Casing-Spears, of which the following is aspecification:

The object of my invention is to loosen casing in oil-wells by jarringwith ordinary drilling-jars, with a hold within, near the bottom, (wherethe sticking always oocurs,) thus obviating the necessity of cutting thesame, which is the method of removal now employed. For this purpose atool is necessary which can take a rm gripe at any point within, and atthe same time one which can be loosened to allow withdrawal when thework is accomplished, and the casing hangs free from above.

In the annexed drawing, S S is a solid, square, tapering iron stem, withpin on top to fit ordinary drilling-tools, and conical guide atbottom,witl1 shoulder Z Z. The four wickers W W are secured by rims R Rto square Vcollar N N, which works up and down on the stem. Steelsprings L L are inserted in the stem,to catch in slots X X in the insideof the square collar, so that on down jarring the wickers can be caughtup and `supported by the springs L L, and the tool withdrawn. The eye Yon the square collar.. secures a line or wire with whichl to liftwickers in case of accident to the springs. The loose collar K K isscrewed onand on, so that the wickers may be removed when necessary.

Figure 3 shows-the method of talring the weightof the casing C fromabove. The yoke M is secured by two chains to clamps Q, at a sufficientwidthapart to allow` jarring to be done by working beam B, to which thetemper-screw T is attached in the usual way to drillingcable anddrilling-tools.

I claim the following: l

The combination of the wickers W VV,fstraps R R, and square collar Nwith the tapering square stem S S, having movable collar K,

spring L, conical point, and shoulders Z Z, all

constructed substantially as and for the purposes set forth. y VICTORGRETTER.

Witnesses:

C. C. BONE, F. A. CONKLE.

